When driving light emitting diodes (LED's), for example, in automotive headlight applications, a dimming switch can be used to turn the LED current ON and OFF very quickly. Without using the dimming switch the output capacitor of a switch mode power supply (SMPS) provides enough energy for the LED current to decay slowly as one would expect. This slow decay causes a wavelength shift in the LED light. This shift is noticeable because the light color changes.